<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <script>
    var arr = ["f","e","i","e","s","o","f","t"];
    
    document.write(arr.join());
     // 输出：f,e,i,e,s,o,f,t
     
     //反转
     arr.reverse();
     
    //  document.write(arr.join()); 
     
     // 输出：t,f,o,s,e,i,e,f

    </script>
</body>

</html>